Control device for spray mixing apparatus



CONTROL DEVICE FOR SPRAY MIXING APPARATUS Filed Dec. l0, 1929 INVFNTOR.

A TTORNEY UNITED STATES PATENT OFFICE CONTROL DEVICE FOR SPRAY MDUNGAPPARATUS Paul L. Geer, Albany, Calif., assigner of threetenths toWesley M.

Wooten, San Francisco,

Calif., and three-tenths to M. C. Frank, Oakland, Calif.

Application December 10, 1929 Serial No. 413,069

Claims.

The invention relates to a control device for apparatus for producing amixed spray, and particularly concerns apparatus in which ingredients ofa mixture are merged at or beyond a dis- 5 charge nozzle therefor.

An object of the invention is to provide for a control of the feed ofthe ingredients at their respective lsources by means entirelycontrolled by an operator at the nozzle.

Another object of the invention is to provide a remote control of theclass described which involves the manual manipulation of but a singledevice by the operator at the nozzle.

A further object is to provide such control means for an air-bornestream of one ingredient that the flow of said ingredient may beprevented while the flow of the carrier air therefor is permitted tocontinue.

Yet another object isy to provide for an airscouring of the pipes orhoses which direct the ingredients from their respective sources to thenozzle by and upon the aforesaid shutting of! of the supply of saidingredients at said sources thereof.

A still further object is to provide improvements in the apparatusdisclosed in my pending application for Letters Patent on a spray mixingmethod and apparatus, Serial Number 353,854, led April 9, 1929, saidimprovements particularly concerning the control of the flow of theingredients from their sources.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth or be apparent in thefollowing description of a typical embodiment of the invention which isillustrated inthe accompanying drawing, in which:

The ligure is al somewhat diagrammatic elevation of a typical apparatusembodying the present invention, certain elements of the apparatus beingpartly broken away or shown in section to disclose details thereof.

As particularly illustrated, the device of the present invention isapplied for controlling the output of a spray-producing apparatus inwhich materials from containers 4 and 5 are conveyed through conduits 6and 7 respectively to a mixing nozzle 8. The iinal disposition of thespray mixture produced by the action of said nozzle is 5o generallyimmaterial; in the present instance it is shown as directed against awall 9 for coating the same. A power-operated compressor 11 is providedfor supplying compressed air for use in the apparatus in a manner to behereinafter disclosed. Conveniently, the containers and the' compressorare mounted on a wheeled vehicle 12 in unitary association and formoving from point to point. The conduits 6 and '7 may be hose or pipes,either wholly or in part, and may be of any desired length to permit theuse of the nozzle at a distance from the said containers and the rest ofthe apparatus.

The present apparatus is particularly arranged for mixing particles of asolid material 13 from the container 4 with a liquid 14 from thecontainer 5. The material 13 may be` any suitable relatively dryaggregate for union with the liquid 14 to provide a coating or othermixture. Said material may, for instance, comprise sand, rockdust,asbestos, sawdust, vegetable fibers, animal flbers, and many otheraggregate materials, either alone or in mixtures, while the liquid 14may correspondingly comprise a suitable binder such as an asphalt, anasphaltic emulsion, a glue, or some other cementitious material. If limeor hydraulic cement are to be used as binders in the product, theseelements might well be mixed dry with the aggregates in the container 4and the liquid 14 would then be water. Furthermore, at least oneingredient of a mix produced by such apparatus might be a gas. And it isto be noted that the product of the apparatus need not be a coating oran adhesive mixture. The present apparatus is particularly arranged forproducing asphaltic coatings wherein the material 13 is sand and/orother aggregates, and the liquid 14 is an asphaltic emulsion whichprovides the binder element of the mix.

Referring now to the container 4, the same is seen to provide a closedcylindrical chamber 15 having at the bottom thereof a suitable devicefor metering the solid material 13 into the duct provided through theconduit 6 and at an adjustably variable rate. As particularly disclosed,the aforesaid metering device comprises a drum member 16 mounted at thebottom of the chamber 15,for rotation about a vertical axis and providedin its peripheral portion with pockets 1'1 extending axiallytherethrough. A pipe 18 extends from the compressor 11 and through thebottom `of the chamber 15 opposite the line of movement of the pocketsto discharge upwardly through successive pockets 17 as they passthereover. A hood element 19 is disposed in the chamber 15 attheopposite side of the drum 16 from and in line with the outlet of thepipe 18, and the passage of said hood is connected through the chamberwall to the inlet end of the conduit 6. In this manner, as a pocket ofthe material 13 becomes aligned with and between the pipe 18 and hood19, the air stream introduced through the pipe 18 conveys the sand fromsaid pocket into the hood and so through the conduit 6 to the nozzle 8,the nozzle passage from the conduit 6 being constantly open.

Means are provided for rotating the metering drum 16 at various speedswhereby to control the flow rate of the material 13 from the container4. As particularly shown, a drive shaft 21 extends downwardly from thedrum 16 and container 4 for geared connection with an air-operated motor22 which receives operating air therefor through a pipe 23 from thecompressor 11. A valve 24 is interposed in the pipe 23 whereby toregulate the operation of the air motor 22; in this manner, the valve 24may be adjustably set to vary the rotative rate of the drum 16 andcorrespondingly vary the flow rate of the material 13 from the container4 by Way of the pockets 17. The now-described metering arrangement forthe material 13 is seen to constitute a metering valve, will on occasionbe hereinafter so referred to, and is intended as the operativeequivalent of a number of devices for the same purpose which are now onthe market.

It is noted that the mutual relations of the drum pockets 17 in themetering device shown are such that an air passage is constantlyprovided between the pipe 18 and hood 19; in this manner, a stopping ofthe drum results in a cleaning out' of the pocket, or pockets,registering with the hood 19, after which a stream of uncharged airtraverses the duct provided by the conduit 6 for scouring the same andfor discharge from the nozzle.

In delivering the liquid 14 from the container 5, said liquid isarranged to be atomized and aerated in a combination atomizing and valvedevice 25 before it is delivered to the conduit 7. The device 25 isdisclosed and described in detail in my copending application for UnitedStates Letters Patent on liquid atomizing and aerating devices, SerialNumber 382,408, filed July 31, 1929. Essentially, said device comprisesa casing providing pressure compartments 26 and 27 separated by aflexible diaphragm 28 of reinforced rubber or the like, and respectivelyconnected with pipes 29 and 31 whereby said compartments are arranged torespectively receive and contain the liquid and air. The said casing isconveniently formed in generally circular and axially separable portions32 and 33 whereby to clamp the diaphragm edge between them, the opposedcasing portions being appropriately cupped or otherwise formed toprovide for a certain degree of axial displacement of the centraldiaphragm portion between certain limiting positions thereof. Asparticularly shown, the diaphragm 28 is disposed in one limitingposition, and its other limiting position is indicated in dash lines.

A tubular boss extends axially from the casing portion 32 and a member34 is mounted thereon to extend generally axially therefrom. The member34 comprises an atomizer and aerator for liquid from the compartment 26,and provides a discharge passage therethrough connecting the compartment26 with the conduit 7. An inner portion of the passage through themember 34 is constricted to provide an atomizing orifice 35 which iscoaxial with the diaphragm 28. The outer portion 36 of the passagethrough the member 34 provides an aerating chamber, air being admittedthereto under pressure from a pipe 37 which discharges radially intosaid chamber at the inner end thereof, the chamber being suitably shapedto provide for a. complete and uniform mixing of air from the pipe 37with the atomized stream from the orice 35.

The casing portion 33 is provided with a tubular and axial boss 38 whichis externally threaded at its free end for the mounting thereon of aclosure member 39, the latter being particularly shown as a cap. Radialopenings are provided through the boss 38 for the respective connectionthereat of the discharge end of the air supply pipe 31 and the inlet endof the pipe 37. For a reason to be hereinafter brought out, a throttlevalve 41 is interposed in the pipe 31 adjacent its point of connectionto the boss 38. For supplying liquid to the compartment 26, the wall ofthe casing portion 32 is provided with an inlet opening at which thedischarge end of the supply pipe 29 is connected, the inletA end of saidpipe extending to the bottom of the container 5. The cavity of thecontainer 5 is connected with the compressor by means of a pipe 42whereby the liquid in the container is arranged to be forced through thepipe 29 by pressure.

The nozzle 8 is so constituted as to effect a uniting of streams ofdifferent materials as they emerge therefrom, there being a centralnozzle passage 43 and a surrounding passage 44 through the nozzle forthe different materials to be mixed. The central nozzle passage 43- isunrestricted and the outer passage 44 is provided with a valve.

As particularly shown, the valve means provided comprises an annular cap45 mounted on the discharge end of the valve body and operative toregulate and close the discharge orifice of the passage 44, said oricebeing in the present instance annular and planar and lying at the end ofan inner tubular body portion which provides the passage 43. The presentnozzle is disclosed and described in greater detail in my pendingapplication for United States Letters Patent on mixing nozzles, SerialNumber 213,483, filed August 17, 1927. Preferably, the solid material isarranged for discharge through the constantly open nozzle passage 43whereby, as has hereinbefore been pointed out, air is constantly emittedtherefrom whether charged or not with the material 13.

Means are provided for effecting a closure of the atomizer orifice 35when the ow of the liquid 14 from the nozzle 8 is to be stopped, saidmeans being controlled by and from the diaphragm 28. Accordingly, and asshown, a member 46 is mounted on the diaphragm to extend 130 axiallytherethrough and Itherefrom, said member providing at the extremitythereof within the compartment 26 a reduced plunger portion 47 forlongitudinal and fitted engagement in and through the orifice 35 asclosure and clean- 135 out for said orifice. Under fluid flowconditions, the plunger 47 is withdrawn from the ori- Iice 35 as shown.The member 46 is generally cylindrical and is guided for axial movementby reason of its engagement in central bores of suitable spidersprovided in the casing portions 32 and 33. A spring 48 is operativebetween the end of the member 46 which extends Within the compartment 27and boss 38 and the closure cap 39 therefor whereby to urge the said 145member to orifice-closing position, the degree of said urge beingadjustable by reason of the adjustment permitted by the threadedengagement of said cap with the boss 38.

'I'he necessary stops for limiting the move- 150 4..

ply to the said ment of the member 46 and the central diaphragm portionwhich controls its portion are both provided in the compartment 27,different portions of the member 46 engaging opposite sides of thecentering spider therein for the purpose. It is to be noted that thedescribed valve devicefor the orifice 35 is described in greater detailin the disclosure o1' the aforesaid application Serial Number 382,408.

The disposition of the diaphragm 28 in the chamber jointly -provided bythe compartments 26 and 27 of the control device 25 is determined by therelative pressures in said compartments and the action of the spring 48,said pressures being different as long as a discharge of uid occursthrough the conduit 7 and from the nozzle passage 44. Under the latterconditions, the pressure in the air compartment 27 will be less thanthat in the liquid compartment 26 wherebythe diaphragm will tend toassume the position shown, the plunger 47 being withdrawn from theorifice 35. The aforesaid pressure difference would be increased to adesired degree by throttling the air supply to the compartment 27 bymeans of the throttle valve 41 in the supply pipe 31, and the effectivepressure to displace the diaphragm to said position 'thereof is resistedby the spring 48.

With the device discharging the aerated liquid, the diierence inpressures in the compartments 26 and 27 is arranged to exceed theresistance of `the spring 48 whereby the plunger 37 is held fullylwithdrawn from the orifice 35 for permitting a free flow of liquidthrough said orifice.y As the nozzle valve is closed, the air pressurein the compartment 27 will build up whereby, as it approaches equalitywith that in the compartment 26, the spring 48 will operate to move thediaphragm to dispose the plunger 47 in orifice-closing position and soshut oif the liquid iiow through the orice. The latter action of thespring is effected suddenly, and is preferablyl arranged to occur beforethe nozzle valve is fully closed whereby air may thereafter continue toiiow through the conduit 7 and nozzle passage 44 while the nozzle valve'is slightly open, said latter air flow effecting a removal of anydeposit or liquid residue from the said conduit and nozzle passage. Areopening of the nozzle valve will eiect a discharge of uncharged airuntil the pressure in `the air compartment 27 is lessened to asufficient degree to permit the static pressure in the compartment 26 todominate for displacing the diaphragm andl plunger to open the orice 35.In lthis manner, the conduit 7 is arranged to be free of liquid exceptwhile the same is owing, and the supply of said liquid to the conduit iscontrolled at its source (the container 5) entirely by the act of anoperator at the nozzle 8 to close the valve of the same, it beingobvious that the specific nozzle valve means is generally immaterial tothe control afforded. A

Remote control means are also provided whereby a corresponding controlof the ilow of solid material from the container 4 may be effected bythe operator at the nozzle. The latter control is effected through aregulation of the power supply to the motor which operates the meteringdrum 16. In the present instance wherein the air-driven motor 22 isprovided, the air supphragm-motor valve 51 interposed in the pipe 23 andhaving its expansion chamber connected by means of a pipe or duct 52with the pipe 37 of motor is controlled by a dia- 4 the liquid aeratingdevice 25 for actuation in accordance with the pressure in the pipe A37.The valve 51 is provided with a spring 53 which is constantly operativeto urge an opening of the valve against the pressure in the expansionchamber of thervalve. At those pressures in the pipe 37 at whichmaterial from the container 5 is permitted to ow from the nozzle 8, thevalve 51 is arranged to be open as shown, but when the pressure` in thepipe 37 becomes great enough to permit the described displacement of thediaphragm, said pressure is also arranged to effect a closing ofthevalve 51. In this manner, the flow of both the solid and liquidmaterials is arranged to be shut off more or less simultaneously attheir sources entirely by and upon a determinable degree of closing ofthe nozzle valve by the operator at the nozzle, no attendant thus beingneeded at the apparatus.

With the present apparatus, the valve 24 is constantly open and is setfor determining the maximum rate of operation of the metering drum 16.Valves 55 and 56 in the conduits 18 and 42 control the air flow to thecontainers4 and5 respectively and are opened to set position at thebeginning of a run. Preferably, and as shown, a three-way valve 57 isinterposed in the duct 52 whereby, at starting, the duct 52 may beclosed oif Iand the expansion chamber of the valve 51 is open to theatmosphere; in this manner, the valve 51 may be rendered inoperativeuntil a normal operating condition is obtained in the apparatus. It isnoted that a primary adjustment of the valves 24, 41, 51 and 56 isnecessary to provide for producing a particular mix of speciflcmaterials from the containers 4 and 5, after which the only necessaryregulation is that automatically provided' through the effect of thepressure in the conduit 7 as said pressure is controlled by the operatorthrough manipulation of the nozzle valve.

In providing for an automatic and remote control of the flow ofmaterials to and through the nozzle, the present apparatus also operatesto generally maintain a constant proportioning of the said materials fordifferent quantity iiow rates from the nozzle between the maximum flowrate and the lowest ilow rate of materials permitted by the describedshut-off device. Thus, a greater pressure in the conduit 7 produced bypartly closing the nozzle valve correspondingly closes the valve 51 toslow the motor 22 and so decrease the delivery rate of solid material tothe nozzle.

Simultaneously, the lowered differential in pressure at opposite sidesof the orice 35 reduces the liquid flow through said orice, with theresult that the ratio of the materials 13 and 14 in the mix is heldsubstantially constant through a determinable range of flow rates fromthe nozzle, said range being primarily determined by the settings of thecap member 39 of the control device 25 and the valve 41.

From the foregoing description taken in connection with the accompanyingdrawing,`the advantages of the construction and method of operation willbe readily understood by those skilled in the art to which the inventionappertains, and while I have described the principle of operation,together with the device which I now consider to be the best embodimentthereof, I desire to have it understood that the device shown is merelyillustrative, and that such changes may be made, when desired, as fallwithin the scope of the appended claims.

Having thus described my invention, I claim as new and dsire to secureby Letters Patent of the United States the following:

1. In spraying apparatus, a discharge nozzle, a conduit through whichto' direct an air-borne sprayable material to said nozzle from a sourcethereof, means connecting the inlet of said conduit with a source ofcompressed air, valve means remote from said nozzle and connecting saidmaterial source with said conduit whereby to variably charge the airstream in the conduit with said material, a second conduit to saidnozzle, a manually-operable valve in said second conduit and at saidnozzle, means connecting said second conduit with a source of compressedair, and means connecting said second conduit with said first valvemeans whereby to control the same in accordance with the pressure insaid second conduit, a closing of said second valve being operativethrough said iirst valve means to shut oi the supply of said material tosaid first conduit.

2. In apparatus of the character described, a discharge nozzle, meansproviding a conduit through which to direct an air-borne sprayablematerial to said nozzle from a source thereof, means connecting saidconduit with a source oi compressed air, a metering valve connectingsaid source of material with said conduit for charging the air thereinwith the said material, a pneumatically operable control means for saidmetering valve, a second conduit to said nozzle, a manually-operablevalve in said second conduit for actuation at the nozzle, meansconnecting said second conduit with a source of compressed air, andmeans connecting said control means with vsaid second conduit foractuation in accordance with the pressure in the latter conduit.

3. In apparatus for mixing and projecting a mixture of solid granularmaterial and a fluid binder for said material, a nozzle, a conduit todirect a stream of said material to said nozzle, a second conduit todirect a stream of said binder to said nozzle, means introducingcompressed air to said conduits whereby said streams are arranged to beair-borne therein and therethrough, a manually actuable valve at saidnozzle and operative solely for controlling the stream iiow in thesecond said conduit, a metering means operative solely to control thesupply otsaid solid material to the ilrst said conduit. and means forautomatic actuation in accordance with the setting of said valve tocorrespondingly control said metering means whereby a closing of saidvalve will prevent a delivery oi' said material to said ilrst conduitindependently of the air flow therethrough.

4. In an apparatus of the character described, a nozzle, means fordelivering iiuid to said nozzle, means for delivering granular materialto said nozzle, said means including a source oi air under pressure, ametering device for said granular material, an air motor driven by saidsource of air under pressure for operating said metering device, a valveon the nozzle for varying the quantity of iluid discharged, and meanswhereby gradual closing of said valve will be accompanied by gradualreduction in the supply of air to said air motor whereby the proportionof uid and granular material discharged from the nozzle will remainconstant.

5. A device of the character described comprising a container forgranular material, a container for liquid, an air operated meteringdevice connected with said container Vfor granular material, a source ofair under pressure, a nozzle, means whereby said air will delivergranular material and liquid to said nozzle and operate said meteringdevice, valve means on the nozzle for controlling the iiow of liquidfrom the nozzle, and means actuated upon operation of said valve meansfor controlling the` flow of air to said metering device whereby theproportion of iluid and granular material discharged from the nozzlewill remain constant.

PAUL L. GEER.

